江淮地区双层拱架塑料大棚通风效果CFD仿真与分析

Simulations and Analysis of Ventilation in the Double-layer-arch Greenhouse Based on the CFD in Jianghuai Region

近年来,双层拱架塑料大棚在江淮地区应运而生,但该类棚型未定,棚内生产小气候问题亟待进一步研究。介绍了双层拱架塑料大棚的应用和研究进展,使用AutoCAD和ProE建立了双层拱架的三维模型,再通过ANSYS ICEM CFD软件将三维模型简化为2-D模型并进行结构化网格划分。针对双层拱架塑料大棚的通风效果分别进行贯流式通风和单面通风的数值模拟分析,结果显示:贯流式通风时内棚和保温层温度分布均匀,并带走棚内热量,有利于双层棚的结构稳定性,能够保证明显的通风效果;单面通风时从内棚进口处开始向另一面,温度呈现阶梯递增形式,最高温度达329 K,最大温差达29 K,保温层温度较均匀、变化不大。因此,采用贯流式通风有利于双层棚的通风效果。仿真与分析结果为双层拱架塑料大棚的实际应用和研究提供理论参考。

In recent years, the double-layer arch greenhouse in Jianghuai region has come into being, but the shed-type has not been determined, the micro-climate issues in the production of the greenhouse need to be studied further. This paper introduced the application and research progress of the double- layer arch mgreenhouse and built a 3D model for the double-layer arch by using AutoCAD and ProE, then simplified the 3 D model into 2D model and divided it on the basis of structured grids. In addition, the ground and plastic film covering of the external shed was handled as temperature wall, and the internal shed was regarded as thermal transmission wall. According to the ventilation effect, numerical simulations were done through tubular and single-sided ventilation respectively for double arch greenhouses. The results showed that temperature in inner layer and internal shed was uniformly distributed and heat in greenhouses could be taken away under the circumstances of tubular ventilation, which was beneficial to the structural stability of double-layer shed and guaranteed the conspicuous ventilation effect. Temperature showed a ladder-like increase from the entrance of internal shed to the other side under the circumstances of ventilation of single- sided. The highest inner temperature could reach 329 K and the maximum temperature difference could be 29 K. The heat conservation showed a uniform distribution and stayed almost stable, so tubular ventilation did well to the double-layer greenhouses. The simulation and analysis result provided a necessary theoretical basis for further promotion and study of the double-layer arch greenhouses.